U.S. patent application number 13/162761 was filed with the patent office on 2012-03-22 for additives for reduction of exhaust emissions from compression ignition engines.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. Invention is credited to Christopher Gallagher, Bradley G. Harrell, Andrew J. McCallum, Jianzhong Yang, Michael J. Zetlmeisl.
Application Number | 20120066964 13/162761 |
Document ID | / |
Family ID | 45816456 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120066964 |
Kind Code |
A1 |
Harrell; Bradley G. ; et
al. |
March 22, 2012 |
Additives for Reduction of Exhaust Emissions from Compression
Ignition Engines
Abstract
Exhaust emissions resulting from the combustion of hydrocarbon
fuels in compression ignition engines may be reduced using a
homopolymer that may be polyisobutylene, polypropylene, and/or
hyperbranched polyalpha-olefins. The homopolymer may have a
molecular weight of from about 1600 to about 275,000. Optionally,
an alkyl nitrate such as 2-ethylhexylnitrate (2EHN), and/or a
peroxide, such as hydrogen peroxide, may also be used together with
the homopolymer. Both NOx and particulate matter emissions (PM) may
be reduced using ppm quantities of the additive compositions;
alternatively, NOx emissions may be lowered or reduced while PM
emissions do not substantially increase.
Inventors: |
Harrell; Bradley G.;
(Pearland, TX) ; Zetlmeisl; Michael J.; (Katy,
TX) ; Gallagher; Christopher; (The Woodlands, TX)
; Yang; Jianzhong; (Missouri City, TX) ; McCallum;
Andrew J.; (Katy, TX) |
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
45816456 |
Appl. No.: |
13/162761 |
Filed: |
June 17, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12128918 |
May 29, 2008 |
|
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13162761 |
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60940914 |
May 30, 2007 |
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Current U.S.
Class: |
44/322 ; 44/324;
585/14 |
Current CPC
Class: |
C10L 1/1258 20130101;
C10L 1/1641 20130101; C10L 1/2222 20130101; C10L 1/1608 20130101;
C10L 1/1811 20130101; C10L 1/1616 20130101; C10L 1/1983 20130101;
C10L 10/02 20130101; C10L 1/143 20130101; C10L 1/1824 20130101;
C10L 1/231 20130101; C10L 1/10 20130101; C10L 1/221 20130101 |
Class at
Publication: |
44/322 ; 585/14;
44/324 |
International
Class: |
C10L 1/18 20060101
C10L001/18; C10L 1/23 20060101 C10L001/23; C10L 1/16 20060101
C10L001/16 |
Claims
1. A method for reducing emissions of a distillate fuel comprising
adding to the distillate fuel an effective amount of an additive
composition for reducing the emissions of the distillate fuel, the
additive composition comprising a homopolymer selected from the
group consisting of polyisobutylene, polypropylene, hyperbranched
polymers, and mixtures thereof, where the homopolymer has a
molecular weight of from about 1600 to about 275,000.
2. The method of claim 1, where the additive composition further
comprises a component selected from the group consisting of an
alkyl nitrate, a peroxide and combinations thereof.
3. The method of claim 2 where the effective amount of the
component ranges from about 100 to about 3000 ppm and the effective
amount of the homopolymer ranges from about 20 to about 2500 ppm,
both based on the total distillate fuel.
4. The method of claim 1 where the fuel has reduced NOx and/or
particulate matter emissions as compared to an otherwise identical
fuel absent the additive composition.
5. The method of claim 1 where the fuel has reduced NOx and
particulate matter emissions are substantially the same as or lower
compared to an otherwise identical fuel absent the additive
composition.
6. A method for reducing emissions of a distillate fuel comprising
adding to the distillate fuel an additive composition comprising:
from about 20 to about 2500 ppm, based on the total distillate
fuel, of a homopolymer selected from the group consisting of
polyisobutylene, polypropylene, hyperbranched polyalpha-olefins,
and mixtures thereof, where the homopolymer has a molecular weight
of from about 1600 to about 275,000; and from about 100 to about
3000 ppm, based on the total distillate fuel, of a component
selected from the group consisting of an alkyl nitrate, a peroxide
and combinations thereof.
7. The method of claim 6 where the fuel has reduced NOx and/or
particulate matter emissions as compared to an otherwise identical
fuel absent the additive composition.
8. The method of claim 6 where the fuel has reduced NOx and
particulate matter emissions are substantially the same as or lower
compared to an otherwise identical fuel absent the additive
composition.
9. An additive composition for reducing the emissions of distillate
fuels comprising: a homopolymer selected from the group consisting
of polyisobutylene, polypropylene, hyperbranched polymers, and
mixtures thereof, where the homopolymer has a molecular weight of
from about 1600 to about 275,000; and a component selected from the
group consisting of an alkyl nitrate, a peroxide, and combinations
thereof.
10. The composition of claim 9 where the volume ratio of
homopolymer to the component ranges from about 1:1 to about
1:100.
11. The composition of claim 9 where the component is an alkyl
nitrate selected from the group consisting of 2-ethylhexyl nitrate
(2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate,
cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and
tetraglycol nitrate.
12. A distillate fuel comprising: a hydrocarbon selected from the
group consisting of diesel fuel, gasoline, jet fuel, and kerosene;
and an effective amount of an additive composition for reducing the
emissions of the distillate fuel comprising a homopolymer selected
from the group consisting of polyisobutylene, polypropylene,
hyperbranched polymers, and mixtures thereof, where the homopolymer
has a molecular weight of from about 1600 to about 275,000.
13. The distillate of claim 12 where the additive composition
further comprises a component selected from the group consisting of
an alkyl nitrate, a peroxide, and combinations thereof.
14. The distillate fuel of claim 13 where the effective amount of
the component ranges from about 100 to about 3000 ppm and the
effective amount of the homopolymer ranges from about 20 to about
2500 ppm, both based on the total distillate fuel.
15. The distillate fuel of claim 12 where the fuel has reduced NOx
and/or particulate matter emissions as compared to an otherwise
identical fuel absent the additive composition.
16. The distillate fuel of claim 12 where the fuel has reduced NOx
and particulate matter emissions are substantially the same or
lower as compared to an otherwise identical fuel absent the
additive composition.
17. The distillate fuel of claim 13 where the component is an alkyl
nitrate selected from the group consisting of 2-ethylhexyl nitrate
(2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate,
cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and
tetraglycol nitrate.
18. A distillate fuel comprising: a hydrocarbon selected from the
group consisting of diesel fuel, gasoline, jet fuel and kerosene;
and an effective amount of an additive composition for reducing the
emissions of the distillate fuel comprising a homopolymer selected
from the group consisting of polyisobutylene, polypropylene,
hyperbranched polymers, and mixtures thereof, where the homopolymer
has a molecular weight of from about 1600 to about 275,000; and a
component selected from the group consisting of an alkyl nitrate, a
peroxide, and combinations thereof; where the fuel has reduced NOx
and/or particulate matter emissions as compared to an otherwise
identical fuel absent the additive composition.
19. The distillate fuel of claim 18 where the effective amount of
the component ranges from about 100 to about 3000 ppm and the
effective amount of the homopolymer ranges from about 20 to about
2500 ppm, both based on the total distillate fuel.
20. The distillate fuel of claim 18 where the component is an alkyl
nitrate selected from the group consisting of 2-ethylhexyl nitrate
(2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate,
cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and
tetraglycol nitrate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part application from
U.S. patent application Ser. No. 12/128,918, filed May 29, 2008,
which claims the benefit of U.S. Provisional Patent Application No.
60/940,914 filed May 30, 2007.
TECHNICAL FIELD
[0002] The present invention relates to additives for distillate
fuels, and more particularly relates, in one embodiment to reducing
exhaust emissions for hydro-carbon fuels using chemical
additives.
TECHNICAL BACKGROUND
[0003] It is well known that considerable effort has been expended
reducing the exhaust emissions from compression ignition (e.g.
internal combustion) engines. These exhaust emissions are the
products of burning the fuel in the engine, emitted from an exhaust
system. The major emissions include hydrocarbons, which are
unburned or partially burned fuels, nitrogen oxides (generally
abbreviated NOx) which are generated when nitrogen in the air
reacts with oxygen under the high temperature and pressure
conditions inside the engine, carbon monoxide (CO) which is a
product of incomplete combustion, and carbon dioxide (CO.sub.2)
which is a product of the complete combustion of hydrocarbons.
[0004] Additives to fuels are known to reduce undesirable
emissions. There are many fuel additives that claim to lower
emissions, such as particulate matter, unburnt hydrocarbon, and
NOx. Various organo-metallic and totally organic formulations have
been proposed and tried. Furthermore, diverse mechanisms have been
proposed for their effectiveness.
[0005] It has been found to be difficult to simultaneously reduce
particulate matter (PM) emissions and NOx emissions, particularly
in diesel fuels. Unfortunately, with some additives, as the PM is
lowered, NOx emissions rise, and vice versa with others. There is
some promise that ethanol fuel additives may help reduce both PM
and NOx simultaneously under certain conditions.
[0006] Thus, it would be desirable if other additives could be
developed to reduce the emissions of distillate fuels upon
combustion.
SUMMARY
[0007] There are provided, in one non-limiting form, compositions
for reducing the emissions of distillate fuels that includes a
homopolymer such as polyisobutylene (PIB), polypropylene (PP),
and/or a hyperbranched polymer, where the homopolymer has a
molecular weight of from about 1600 to about 275,000. Combinations
of these polymeric materials with an alkyl nitrate, such as
2-ethyhexylnitrate (2EHN), and/or a peroxide, such as hydrogen
peroxide, are also useful.
[0008] There are further provided in another non-restrictive
version distillate fuels, such as diesel fuels, gasoline, jet
fuels, or kerosene, having reduced emissions, that contains an
effective amount of a composition to reduce emissions of a
homopolymer that may be polyisobutylene, polypropylene, and/or a
hyperbranched polymer, where the homopolymer has a molecular weight
of from about 1600 to about 275,000, and optionally an alkyl
nitrate and/or a peroxide.
[0009] Also provided in another non-limiting embodiment are methods
for reducing emissions of a distillate fuel by adding to the fuel
an effective amount of a composition that includes a homopolymer
that may be polyisobutylene, polypropylene, and/or a hyperbranched
polymer, where the homopolymer has a molecular weight of from about
1600 to about 275,000, and optionally an alkyl nitrate and/or a
peroxide.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a graph of NOx emissions in a distillate fuel
showing NOx reduction measured as % as a function of total
concentration of the additives herein;
[0011] FIG. 2 is a graph of particulate matter emissions measured
as a function of the total concentration of the additives for the
fuels of FIG. 1;
[0012] FIG. 3 is another graph of NOx emissions in a distillate
fuel showing NOx reduction measured as % as a function of total
concentration of an additive composition containing 10%
hyperbranched polyalpha-olefin (HPAO) and 70% 2-ethylhexyl nitrate
(EHN), the balance being solvent; and
[0013] FIG. 4 is a graph of particulate emissions (PM) in a
distillate fuel showing NOx reduction measured as % as a function
of total concentration of an additive composition containing 10%
hyperbranched polyalpha-olefin (HPAO) and 70% 2-ethylhexyl nitrate
(EHN), the balance being solvent.
DETAILED DESCRIPTION
[0014] The methods and compositions herein relate to reducing the
amount of exhaust emissions resulting from the combustion of
hydrocarbon fuels in compression ignition engines such as internal
combustion engines. In particular, the additives reduce NOx
emissions and/or particulate matter. More specifically, the methods
and compositions herein concern a fuel additive formulation that
includes a polymer. Suitable polymers are homopolymers including,
but not necessarily limited to, polyisobutylene, polypropylene,
hyperbranched polymers, and in particular hyperbranched
polyalpha-olefins (PAO), and the like. In one non-restrictive
version, the hyperbranched polyalpha-olefins may be hyperbranched
polymers of C4-C30 alpha-olefins, where the alpha-olefins may be
acid- or alcohol-functionalized, and mixtures and derivatives
thereof. In one non-limiting embodiment, the polymer presence
lowers NOx and in many embodiments also lowers particulate matter
(PM).
[0015] The additive composition herein may also optionally contain
a component that may be an alkyl nitrate and/or a peroxide.
Suitable alkyl nitrates include, but are not necessarily limited
to, 2-ethylhexyl nitrate (2EHN),
CH.sub.3(CH.sub.2).sub.3CH(C.sub.2H.sub.5)CH.sub.2ONO.sub.2,
iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate, cyclohexyl
nitrate, dodecyl nitrate, diglycol nitrate and tetraglycol nitrate
and the like. Ether nitrates and fatty acid nitrates may also be
useful. The alkyl nitrate may function to primarily lower the NOx
emissions although reduction in PM may also be expected.
Alternatively, NOx emissions may be lowered by the compositions
herein without appreciably raising PM levels, which would also be
an advantage and an improvement.
[0016] The additive composition may also optionally include a
peroxide, in place of or in addition to the alkyl nitrate. Suitable
peroxides include, but are not necessarily limited to, hydrogen
peroxide, di-tertiary butyl peroxide, and benzoyl peroxide and the
like. Further, some synergism has been found between the
homopolymer and the alkyl nitrate and/or peroxide. Known cetane
boosters for use in distillate fuels include 2-ethylhexyl nitrate,
tertiary butyl peroxide, diethylene glycol methyl ether,
cyclohexanol, and mixtures thereof. Conventional, known ignition
accelerators include hydrogen peroxide, benzoyl peroxide,
di-tert-butyl peroxide, and the like.
[0017] By hyperbranched polyalpha-olefins are meant polymers
prepared by polymerizing hydrocarbons under free radical conditions
at low pressures. Suitable free radical catalysts include, but are
not necessarily limited to, metallocenes and transition metal
catalysts, along with peroxide catalysts and Ziegler-Natta
catalysts. The polymers are unique in that although hydrocarbon
polymers generally have higher molecular weight, greater viscosity
and greater hardness than the starting hydrocarbon these polymers
generally have higher melting points and congealing points than the
starting hydrocarbons. The hydrocarbons employed are primarily
alpha-olefins of the formula RCH.dbd.CH.sub.2 but may also include
alpha-olefins having vinylidene structures, internal olefins and
saturates, where R is an alkyl or alkylene group, including those
having vinylidene structures. Suitable hyperbranched
polyalpha-olefins are those made according to the methods described
in U.S. Pat. Nos. 4,060,569; 4,239,546 and 6,776,808, all
incorporated by reference herein in their entirety. The
hyperbranched polyalpha-olefins are considered homopolymers herein
under the classic definition because they are made from a single
monomer. Suitable hyperbranched polyalpha-olefins herein may have a
number average molecular weight (M.sub.n) of from about 100 to
about 275,000, alternatively a lower threshold of about 150 and
independently an upper threshold of about 250,000, and in another
non-limiting embodiment from about 200 independently up to about
175,000, or even up to about 125,000. Alternative lower thresholds
to be used within these ranges include, but are not necessarily
limited to, about 1600, about 1700 and about 1800, even about 2000.
The patents noted above do describe copolymers which are not
encompassed by the additive compositions and methods herein.
[0018] Hyperbranched polyalpha-olefins have a unique physical and
chemical structure compared with conventional homopolymers of
ethylene, propylene, butylene (1- or 2-), pentylene or isobutylene.
Hyperbranched polyalpha-olefins have long alkyl groups on tertiary
carbons and "branches on branches". By "long alkyl groups" is meant
alkyl groups of from 4 to 50 carbon atoms; alternately from 4 to 24
carbon atoms, and in another non-limiting embodiment, from 4 to 14
carbon atoms. Hyperbranched polyalpha-olefins are expected to have
at least two alkyl branches on at least two other alkyl branches,
whereas conventional homopolymers noted above have no such
"branching on branching". This is in contrast to polyisobutylene,
which at most has methyl "branches". Indeed, the maximum alkyl
branch length from the conventional homopolymers in the list above
is C3, and again, they have no branches on branches.
[0019] Other polymers that may also be useful in the additive
compositions herein include, but are not necessarily limited to,
isotactic polypropylene (such as ones having a weight average
molecular weight in the range of about 1600 to about 2000;
alternatively about 1700 to about 2000) or higher molecular weight
hyperbranched polymer products than those described above. Polymer
alone without the 2EHN may be useful.
[0020] Suitable homopolymers include, but are not necessarily
limited to polyisobutylene, polypropylene, hyperbranched polymers,
and mixtures thereof, where the homopolymer has a M.sub.n molecular
weight of from about 1600 to about 275,000; alternatively the lower
M.sub.n threshold is about 1600, about 1700, about 1800 or about
2000, where alternatively the upper threshold, in combination with
any of the lower thresholds, may be about 275,000, about 250,000,
about 175,000, or about 125,000 to give acceptable alternative
M.sub.n ranges.
[0021] The methods herein relate to additive compositions for
distillate fuels, as contrasted with products from resid. In the
context herein, distillate fuels include, but are not necessarily
limited to diesel fuel, kerosene, gasoline, jet fuel, and the like.
It will be appreciated that distillate fuels include blends of
conventional hydrocarbons meant by these terms with oxygenates,
e.g. alcohols, such as methanol, ethanol, and other additives or
blending components presently used in these distillate fuels, such
as MTBE (methyl-tert-butyl ether), or that may be used in the
future. In one non-limiting embodiment herein, distillate fuels
include low sulfur fuels, which are defined as having a sulfur
content of 0.2% by weight or less, and in another non-limiting
embodiment as having a sulfur content of about 0.0015 wt. % or
less--such as the so-called "ultra low sulfur" fuels. Particularly
preferred hydrocarbon fuels herein are diesel and kerosene. It is
expected that a more conventional diesel fuel (i.e. with an
aromatic content of >28%) treated with the additive composition
herein will be equivalent in emissions to a Texas Low Emissions
Diesel (TxLED) fuel with <10% aromatic content.
[0022] Generally, in one non-limiting embodiment herein the
composition for improving the emissions of distillate fuels is a
mixture or blend of 2EHN (or a peroxide component) and at least one
of the homopolymers. In another non-restrictive version herein the
homopolymer is present in the fuel in the range of about 20 to
about 2500 ppm, in one non limiting embodiment from about 20
independently up to about 300 ppm; alternatively from about 20
independently up to about 150 ppm. The alkyl nitrate, particularly
2EHN, may be present in the fuel in the range of about 100 to about
3000 ppm, alternatively from about 500, independently up to about
1500 ppm. In one non-limiting embodiment, the volume ratio of
homopolymer to the component ranges from about 1:1 to about 1:100,
and alternatively the volume ratio of homopolymer to the component
ranges from about 1:2 to about 1:10; and in one particularly
suitable ratio, about 1:7.
[0023] Typically, a solvent may be advantageously used in the
compositions herein, where the solvent may be aromatic solvents and
pure paraffinic solvents. Aromatic solvents are particularly
preferred. The proportion of solvent in the total fuel additive
composition may range from about 0 to 90 weight %; in another
non-restrictive embodiment, the solvent may range from a lower
threshold of about 15 wt % independently to an upper threshold of
45 wt %. The use of a solvent is optional. In some non-limiting
embodiments, no solvent is used or desired. A non-restrictive
example would be 87.5% 2EHN and 12.5% HPAO with no solvent (a 7:1
ratio of active components). Specific examples of suitable solvents
include, but are not limited to paraffins and cycloparaffins,
aromatic naphtha, kerosene, diesel, gasoline, xylene, toluene,
alcohols (e.g. 2-ethylhexanol), and the like.
[0024] It will be appreciated that the methods and compositions
herein also encompass distillate fuels containing the additive
compositions described herein, as well as methods of improving the
emissions properties of distillate fuels using the additive
compositions described herein.
[0025] Other, optional components of the distillate fuels in
non-limiting embodiments may include, but are not necessarily
limited to detergents, pour point depressants, cetane improvers,
lubricity additives, dehazers, cold operability additives,
conductivity additives, biocides, dyes, and mixtures thereof.
Particularly useful components may include condensation reaction
products of aldehydes and amines which are useful as antioxidants
and are effective to lower PM and unburnt hydrocarbon (HC). A
specific non-limiting example is the condensation reaction product
between formaldehyde and di-n-butylamine. In another non-limiting
embodiment, water is explicitly absent from the additive
composition.
[0026] The invention will be illustrated further with respect to
the following non-limiting Examples that are included only to
further illuminate the invention and not to restrict it.
Examples 1-3
[0027] Additive compositions expected to be useful herein include,
but are not necessarily limited to the following outlined in Table
I:
TABLE-US-00001 TABLE I Fuel Additive Compositions to Reduce Exhaust
Emissions Ex. Polymer 2EHN Solvent Other 1 10 wt % PIB 70 wt % 15
wt % aromatic 5 wt % 2-ethylhexanol 2 10 wt % hyper- 70 wt % 15 wt
% aromatic branched polymer 5 wt % 2-ethylhexanol 3 70 wt % 10 wt %
aromatic 20 wt % Product Q The hyperbranched polymer is a
polyalpha-olefin having a molecular weight of about 2800. The
2-ethylhexanol (2EH) was added as a solvent to improve the low
temperature stability of the additive formulation. Product Q is a
condensation reaction product between formaldehyde and
di-n-butylamine.
Examples 4-9
[0028] Other additive compositions expected to be useful herein
include, but are not necessarily limited to those outlined in Table
II:
TABLE-US-00002 TABLE II Component Description Wt-% Ex. 4 PIB, 1500
MW 10 2-Ethylhexyl nitrate 70 Aromatic solvent 15 2-Ethylhexanol 5
Ex. 5 Hyperbranched PAO 10 2-Ethylhexyl nitrate 70 Aromatic solvent
15 2-Ethylhexanol 5 Ex. 6 2-Ethylhexyl nitrate 70
bis-(dibutyl)diaminomethane 20 Aromatic solvent 10 Ex. 7 PIB, 1500
MW 50 Aromatic solvent 45 2-Ethylhexanol 5 Ex. 8 Hyperbranched PAO
50 Aromatic solvent 45 2-Ethylhexanol 5 Ex. 9 PIB, 1500 MW 10
2-Ethylhexyl nitrate 70 Aromatic solvent 10 Polyester diol (for
lubricity) 5 2-Ethylhexanol 5
[0029] The test data in the Figures discussed below was developed
using a 1991 DDC Series 60 (Serial No. 06R0038671) heavy duty
diesel engine mounted in a transient-capable test cell. This engine
had an in-line, six cylinder configuration rated for 365 hp at 1800
rpm, was turbocharged, and used a laboratory water to air heat
exchanger for a charge air intercooler. The exhaust was routed to a
full flow constant volume sampler that utilized a positive
displacement pump. Total flow in the tunnel was maintained at a
nominal flow rate of about 2000 SCFM. Sample zone probes for
particulate matter (PM), heated oxides of nitrogen (NOx), heated
hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2)
measurements were connected to the main tunnel. Probes for
background gas measurement were connected downstream of the
dilution air filter pack, but upstream of the mixing section. The
dilution system was equipped with pressure and temperature sensors
at various locations in order to obtain all necessary information
required by the U.S. Code of Federal Regulation (40 CFR, Part 86,
Subpart N).
[0030] FIG. 1 depicts the NOx mitigation that is achieved with
various formulations of HPAO and PIB, alone and in combination with
EHN in a compression ignition fuel. The y-axis indicates the
percent NOx reduction. The x-axis indicates the total concentration
in ppm (wt.) of the additive component or components for a
particular test. FIG. 1 illustrates several points: [0031] 1. All
of the formulations mitigated NOx, at least to some extent. [0032]
2. PIB alone performed considerably better than HPAO alone. [0033]
3. The combinations of polymer plus EHN performed better than
polymer alone or EHN alone. [0034] 4. The HPAO plus EHN combination
performed better than the corresponding combination with PIB, in
spite of the fact than PIB alone performed better than HPAO alone.
[0035] 5. The HPAO plus EHN combination performed better at 2000
ppm than EHN alone at 3000. This point becomes even more
significant when the fact is considered that the combination
product at 2000 ppm has a total of 1600 ppm active components (1400
EHN and 200 HPAO). This clearly indicates a synergism between HPAO
and EHN.
[0036] FIG. 2 depicts the PM emissions that were achieved with the
distillate fuels and the additives of FIG. 1. HPAO and EHN alone
did not affect PM. PIB alone gave slightly increased PM (slightly
negative reduction). It may be noted that at about 1600 ppm total
concentration, the fuel with 1400 ppm EHN and 200 ppm PIB had
improved PM reduction. At about 2400 ppm total concentration, 2100
ppm EHN and 300 ppm PIB, the PM emissions increased (negative
reduction). At about 1600 ppm total concentration, 1400 EHN and 200
ppm HPAO gave somewhat increased PM emission, but at about 2400 ppm
total concentration, 2100 ppm EHN and 300 PIB gave no PM
change.
[0037] FIG. 3 depicts data on one formulation, 10% HPAO/70% EHN in
six different distillate fuels that met ASTM D975 specifications,
but varied in composition, at various dosages. The y-axis is the
same as in FIG. 1, but the x-axis is ppm of the additive as
formulated. In every case the effectiveness of the additive is
clear, but the degree of effectiveness varies from fuel to fuel.
For instance, at an additive dosage of 2500 ppm (as formulated) NOx
reduction was as high at 7% in the fuel with the best response and
as low as about 3% in the fuel with the worst response.
[0038] In addition to the effectiveness of the HPAO and HPAO-EHN
combinations in mitigating NOx, there is clear evidence that these
components do so without increasing particulate matter to any
significant extent and, in fact, in most cases it actually lowers
PM. FIG. 4 is illustrative of this point. In two of the three fuels
PM was mitigated by as much as about 7%, whereas in one fuel there
was a very slight, and most likely not statistically significant,
increase in PM. Another different fuel, Fuel E, gave a more
pronounced negative reduction in PM (increase in PM) than Fuel C.
Without being limited to any particular explanation, it may be that
this Fuel E behavior was due to high aromatics content and an
unusually high specific gravity.
[0039] In the foregoing specification, the invention has been
described with reference to specific embodiments thereof, and has
been demonstrated as effective for reducing the emissions of fuels.
However, it will be evident that various modifications and changes
can be made thereto without departing from the broader spirit or
scope of the invention as set forth in the appended claims.
Accordingly, the specification is to be regarded in an illustrative
rather than a restrictive sense. For example, specific combinations
of polymers optionally together with alkyl nitrates and/or
peroxides falling within the claimed parameters, but not
specifically identified or tried in a particular composition to
improve the emissions of fuels herein, are expected to be within
the scope of this invention. Certain compositions under certain
conditions may serve to lower NOx emissions without any substantial
increase in PM emissions or with substantially unchanged PM
emissions. It is anticipated that the compositions of this
invention may also impart to the engines in which they are used as
emissions reducers, greater horsepower, and better fuel economy as
a result of less friction, whether they are used in diesel or
gasoline engines.
[0040] The present invention may suitably comprise, consist or
consist essentially of the elements disclosed and may be practiced
in the absence of an element not disclosed.
[0041] The words "comprising" and "comprises" as used throughout
the claims is to interpreted "including but not limited to".
* * * * *